Hyperthermia is a technique for treating cancerous tissue cells involving the application of heat in the vicinity of the cancer cells. The cancer is selectively destroyed after several treatments. This technique has been successfully employed for cancers that can be externally treated.
However, some cancers are located such that they cannot be successfully treated with conventional external techniques. For example, certain lung cancers are too remote from the radiation to be successfully treated by a microwave electrode located adjacent the skin of the user. The heat generated by the electrode is such that it destroys noncancerous tissue if left in contact with such tissues for a sufficient time to affect cancerous tissue. Heretofore, water has not been suitable as a cooling medium because microwave energy can be absorbed by a water shield greater than about one millimeter thick.